The company sold equity worth $112.52 million on April 6, according to an SEC filing. It listed Jared Birchall, president of Musk’s Neuralink startup, and SpaceX Director Steve Davis, as people “related” to the company. It appears that billionaire Musk, who also leads Tesla and SpaceX, likely put in more than $100 million.

“Over 90% of this funding round came from Elon, with the rest from early employees,” the Boring Company said in a statement, adding that no outside investors were involved. The fundraising news was reported earlier by Axios.com.

Musk has promoted his new operation for the past year, and it’s aggressively pursuing projects in Los Angeles, Chicago and line that would run between New York and Washington. An initial tunnel in Hawthorne, the Los Angeles suburb where both it and SpaceX are headquartered, is already built and permits are being sought to expand that project.

A Loop transportation pod that may someday run in tunnels built by Elon Musk's Boring Co.

The Boring Company

The company’s intention is to build tunnels with custom-designed excavation machines for Hyperloops, Musk’s long-envisioned vacuum tube train idea to ferry passengers between cities at speeds in excess of 600 miles per hour. The tunnels could also be designed for smaller “Loops,” high-speed transportation pods on autonomous “electric skates” traveling at up to 150 miles per hour, according to Boring Co.’s website. The pods could hold up to 16 passengers as a type of mass-transit system or transport individual vehicles beneath city streets.